president obama, along with first lady michelle obama bowing their heads in prayer mourning all those who perished. many of those, relatives of the victims. just as in years past they read their loved ones' names aloud. >> i wish you could see how big dunn and phillip are now. that my uncle martin michael worely, we miss you. >> it was a day like this one, a clear blue sky, but a sky that would soon be filled with clouds of smoke and prayers of a nation shaken to its core. >> reporter: and in pennsylvania, vice president joe biden laying a wreath to those who died. the worst terror attack in u.s. history on the minds of all, general john allen taking the time to reconfirm our commitment. >> 11 years from that day there should be no doubt that our dedication to this commitment remains strong and unshaken. >> reporter: a metal beam from the original towers, the base of a 9/11 monument in jerusalem, joined there by relatives of israeli victims who urged the entire world to never forget. >> let all the souls of the thousands of victims whose names are marked on this memorial in jerusalem